Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chiet tach, chieu sang
dong trong » duong trong, dung trong, cong trong
hieu quan » hieu qua, lieu quan, thien quan
trung cua » truong cua, trung tuan, trung cap
trong tac » trong cac, tuong tac, trong tan
cua dong » chua dong, cua cong, cua dang
quan cao » quang cao, quan cau, quan ao

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sach) OR (hieu quan)) - thanh trung cua dong trong tac quan cao~.
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sach) or (hieu quan)) - thanh trung cua dong trong tac quan cao*.